Successful Cochlear Implantation of a Split Electrode Array in a Patient With Far-advanced Otosclerosis Assisted by Electromagnetic Navigation: A Case Report

Comparison of the efficacy of cochlear implantation and stapes surgery in far advanced otosclerosis: a meta-analysis study

OBJECTIVE

This study is to compare the hearing outcomes and complications of stapes surgery and cochlear implantation (CI) in patients with far-advanced otosclerosis (FAO).

DATA SOURCES

A comprehensive electronic search of PubMed/MEDLINE, Scopus, Web of science and Cochrane Library was conducted in June 2021 for articles in the literature till this year.

STUDY SELECTION

Studies are published in English language, conducted on human subjects, concerned with comparison of CI and stapes surgery in the management of FAO, not Laboratory study and not Opinion study. The current review followed the guidelines of preferred reporting items for systematic reviews and meta-analysis statement 2009 (PRISMA).

DATA EXTRACTION

Twenty-six studies were included with 334 patients in CI group and 241 patients in stapes surgery group. Comparison between both groups was done in terms of postoperative complications, audiological outcomes, rete of revision surgery and patients' satisfaction rate.

RESULTS

Postoperative complications rate was significantly lower in CI (13.6%) than stapes surgery (18.6%). CI had a significantly lower rate of revision surgery (8.1%) than stapes surgery (16.4%). CI had a better mean for pure tone average (29.1 dB) than stapedectomy (52.3 dB) while stapes surgery had a higher mean for recognition of monosyllables and disyllables than CI. CI had significantly higher satisfaction rate than stapes surgery.

CONCLUSION

Both Stapes surgery and CI are reliable treatment options for FAO with close success rates. Statistics of CI are greater than stapes surgery and CI has a consistent improvement in audiometric outcomes in comparison to stapes surgery.

Cochlear Implant Outcomes in Patients With Otosclerosis: A Systematic Review

OBJECTIVE

This study aimed to establish hearing outcomes after cochlear implantation in patients with otosclerosis.

MATERIALS AND METHODS

We conducted a systematic review and narrative synthesis. Databases searched were as follows: MEDLINE, PubMed, Embase, Web of Science, Cochrane Collection, and ClinicalTrials.gov . No limits were placed on language or year of publication. The review was conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses statement.

RESULTS

Searches identified 474 abstracts and 180 full texts, with 68 studies meeting the inclusion criteria and reporting outcomes in a minimum of 481 patients with at least 516 implants. Patient-reported outcome measures (PROMs) were reported in five studies involving 51 patients. Intraoperative adverse events/surgical approach details and preoperative radiological assessment were reported in 46 and 38 studies, respectively. The methodological quality of included studies was modest, predominantly consisting of case reports and noncontrolled case series with small numbers of patients. Most studies were Oxford Centre for Evidence Based Medicine grade IV.

DISCUSSION

Access to good rehabilitation support is essential to achieving the good hearing outcomes and PROMs that can be expected by 12 months after implantation in most cases. There was a significant association between the radiological severity of otosclerosis and an increase in surgical and postoperative complications. Postoperative facial nerve stimulation can occur and may require deactivation of electrodes and subsequent hearing detriment.

CONCLUSIONS

Hearing outcomes are typically good, but patients should be counseled on associated surgical complications that may compromise hearing. Modern diagnostic techniques may help to identify potentially difficult cases to aid operative planning and patient counseling. Further work is needed to characterize PROMs in this population.

Cochlear Implantation in Advanced Otosclerosis: Pitfalls and Successes

Purpose of Review

This review will highlight recent outcome-based evidence guiding decision making for cochlear implantation in advanced otosclerosis, related complications, and technical surgical considerations in otosclerosis and the obstructed cochlea.

Recent Findings

Cochlear implantation in advanced otosclerosis results in consistent, excellent auditory outcomes with improvement in both objective speech recognition scores and subjective quality of life measures. Facial nerve stimulation may occur at higher rates in otosclerosis cochlear implant recipients. Cochlear implantation in the setting of luminal obstruction in osteosclerotic patients may be managed with altered surgical technique to achieve successful auditory improvements. Pre-operative imaging with high resolution CT or MRI may help anticipate intraoperative challenges and post-operative complications in cochlear implantation.

Summary

Cochlear implantation is an established, successful treatment for profound hearing loss in advanced otosclerosis. Surgeon knowledge of outcomes, complications, and potential surgical challenges is important to appropriately counsel patients regarding auditory rehabilitation options in advanced otosclerosis.

Freehand Stereotactic Image-Guidance Tailored to Neurotologic Surgery

Hypothesis: The use of freehand stereotactic image-guidance with a target registration error (TRE) of μ_TRE + 3σ_TRE < 0.5 mm for navigating surgical instruments during neurotologic surgery is safe and useful. Background: Neurotologic microsurgery requires work at the limits of human visual and tactile capabilities. Anatomy localization comes at the expense of invasiveness caused by exposing structures and using them as orientation landmarks. In the absence of more-precise and less-invasive anatomy localization alternatives, surgery poses considerable risks of iatrogenic injury and sub-optimal treatment. There exists an unmet clinical need for an accurate, precise, and minimally-invasive means for anatomy localization and instrument navigation during neurotologic surgery. Freehand stereotactic image-guidance constitutes a solution to this. While the technology is routinely used in medical fields such as neurosurgery and rhinology, to date, it is not used for neurotologic surgery due to insufficient accuracy of clinically available systems. Materials and Methods: A freehand stereotactic image-guidance system tailored to the needs of neurotologic surgery-most importantly sub-half-millimeter accuracy-was developed. Its TRE was assessed preclinically using a task-specific phantom. A pilot clinical trial targeting N = 20 study participants was conducted (ClinicalTrials.gov ID: NCT03852329) to validate the accuracy and usefulness of the developed system. Clinically, objective assessment of the TRE is impossible because establishing a sufficiently accurate ground-truth is impossible. A method was used to validate accuracy and usefulness based on intersubjectivity assessment of surgeon ratings of corresponding image-pairs from the microscope/endoscope and the image-guidance system. Results: During the preclinical accuracy assessment the TRE was measured as 0.120 ± 0.05 mm (max: 0.27 mm, μ_TRE + 3σ_TRE = 0.27 mm, N = 310). Due to the COVID-19 pandemic, the study was terminated early after N = 3 participants. During an endoscopic cholesteatoma removal, a microscopic facial nerve schwannoma removal, and a microscopic revision cochlear implantation, N = 75 accuracy and usefulness ratings were collected from five surgeons each grading 15 image-pairs. On a scale from 1 (worst rating) to 5 (best rating), the median (interquartile range) accuracy and usefulness ratings were assessed as 5 (4-5) and 4 (4-5) respectively. Conclusion: Navigating surgery in the tympanomastoid compartment and potentially in the lateral skull base with sufficiently accurate freehand stereotactic image-guidance (μ_TRE + 3σ_TRE < 0.5 mm) is feasible, safe, and useful. Clinical Trial Registration: www.ClinicalTrials.gov, identifier: NCT03852329.

Is There a Role for Intraoperative Navigation During Cochlear Implantation in Patients With Aural Atresia?

OBJECTIVE

Concurrent bilateral congenital aural atresia (CAA) and profound sensorineural hearing loss are rare. While not a contraindication, temporal bone and cochleovestibular abnormalities are an important consideration for cochlear implantation (CI) candidacy. Intraoperative image-guided surgical navigation may play a role during CI surgery in patients with complex anatomy, such as CAA.

PATIENT

One patient with bilateral CAA, cochlear dysplasia, speech delay, and profound sensorineural hearing loss underwent candidacy evaluation for cochlear implantation.

INTERVENTIONS

Cochlear implantation using intraoperative image-guided navigation.

MAIN OUTCOME MEASURES

(1) Registration accuracy, (2) surgical outcomes, (3) audiometry.

RESULTS

A four-year-old girl with complete bilateral CAA and profound sensorineural hearing loss successfully underwent a right transmastoid approach for CI using intraoperative image-guided navigation with sticker fiducials. Bony landmarks included the mastoid tip, tympanomastoid suture line, helical root, zygomatic root, and lateral brow. A registration accuracy of 0.9 mm was achieved. There were no intraoperative or immediate postoperative complications. Postoperatively, Neural Response Imaging was confirmed on 9 electrodes and behavioral testing demonstrated Ling-6 access at 30 dB. On most recent follow-up, she has demonstrated gains in language development, vocalizations, and uses total communication in a hearing-impaired educational environment.

CONCLUSIONS

Children with CAA and profound sensorineural hearing loss may be candidates for cochlear implantation, with successful outcomes in the setting of complex anatomy. Surgical navigation may play a role corroborating intraoperative landmarks.

Special electrodes for demanding cochlear conditions

Optimal matching of an electrode array to the cochlear anatomy plays a key role in bringing the best benefit of CI technology to the users. Even within the category of normal anatomy cochlea, the size variation is huge justifying MED-EL's FLEX electrode array to be available in five different lengths. Within the malformed inner-ear category the anatomical variation is huge, convincing MED-EL to custom-design the electrode array as per the request from the operating surgeons. Thanks to G. Bredberg, M. Beltrame, L. Sennaroglu, J. Gavilan, S. Plontke, T. Lenarz, J. Müller, and few others for their valuable suggestions on unique electrode designs satisfying various needs. Translational research efforts at MED-EL in cooperation with CI surgeons from across the world led to the implantation of a variety of electrode array designs in patients with special cochlear needs.

Pre- and post-operative imaging of cochlear implants: a pictorial review

Cochlear implants are increasingly used to treat sensorineural hearing disorders in both children and adults. Pre-operative computed tomography and magnetic resonance imaging play a pivotal role in patient selection, to rule out findings that preclude surgery or identify conditions which may have an impact on the surgical procedure. The post-operative position of the electrode array within the cochlea can be reliably identified using cone-beam computed tomography. Recognition of scalar dislocation, cochlear dislocation, electrode fold, and malposition of the electrode array may have important consequences for the patient such as revision surgery or adapted fitting.